Method of making mercury switches



Oct. 31, 1933. J. M. PAGAN I METHOD OF MAKING MERCURY SWITCHES Filed Aug. 27, 1930 IIIII Patented Oct. 31, 1933 UNITED STATES 1,933,323` y METHOD oF MAKING MERCURY SWITCHES James- M. Fagan, Maplewood, N. J., assigner to Westinghouse Lamp Company, a, corporation of Pennsylvania Application August 27, 1930. Serial No. 478,023 3 ClaIIlS.y (C1. 20o-15,2)

This invention relates to the manufacture of mercury switches and relates more particularly to a mercury switch including a plurality of electrodes arranged to support a refractory member.

An object of the invention is to provide a mercu'ry switch of a simple and economical construction.

Another object of the invention is to provide a mercury switch in which the operation of exhausting a sealed envelope. is facilitated.

Anotherobject of the invention is tol provide a mercury switch in which a mercury pool may be introducedIand the sealed envelope ofthe switch exhausted without a removal of the mercury. l

Other objects and advantages of the invention will be evident from the following description together with the accompanying drawing in which,

Fig. 1 is a longitudinal sectional view of a mercury switch constructed in accordance with the present invention;

Fig. 2 is a view taken on lines II-II in Fig. 1;

Fig. 3 is a side elevational view of the parts of a switch shown in cross section and positioned in a holder for a sealing in operation;

Fig. 4 is a plan view of the holding device shown in Fig. 3, and

Fig. 5 is a sectional view of a mercury switch showing the position of the mercury during an exhausting operation.

The selected embodiment of the invention as illustrated shows a mercuryswitch comprising a bulb 10 having therein a refractory element 11. The said refractory element is provided withA a cavity 12 and an inclined surface 13, electrodes 14 and 15 extending through a squashed portion or press 16.

An end 17 of electrode 14 is tightly tted into an aperture in the bottom of the cavity 12. An end 18 of electrode 15 is inserted in an aperture extending into the lower end of the inclined surface 13. A mercury pool 19 is positioned in the envelope 10 and when the device -is in a horizontal position as shown in Fig. 1,

the mercury pool contacts only with the elec.- trode 15. When the device is tipped the mercury flows into the cavity 12 leaving therein a stationary pool 2l..

The foregoing generally describes the switch construction which is generally the same as shown in Patent No. 1,762,213. The said patent, however, provides means for exhausting the envelope by a tubulatu're which results in a tip at the rounded portion of the sealed envelope or bulb.

Thepresent invention relates to an improved construction in which an exhaust tube is pro- -vided and so arranged that a portion 22 of the exhaust tube extends from the press 16 into the bulb and may be conveniently supplied with a quantity of mercury as for example by the method shown in Patent 1,871,311. An opposite end 23 of the exhaust tube may be tipped off in the usual manner after the sealed'envelope or bulb 10 has been exhausted.

Means `for constructing a device as above described are shown in Figs. 3 and 4 and may comprise a pair of jaws 24 and 25 arranged to hold the bulb 10. A support rod 26 is provided and ends 27 and 28 of the electrodes 14 and 15 respectively are inserted in apertures in the support rod to hold the electrodes and the refractory member while the bulb is placed thereover.

Support rod 26 is provided with a central bore or aperture 29 to receive an exhaust tube 31 to hold the same centrally within the bulb 10. Extending upwardly from the bottom of the aperture 29 is a mandrel rod 32 having a reduced portion 33 to receive a metallic or refractory sleeve 34, and so arranged as to hold the sleeve Within the exhaust tube in position adjacent to the neck portion 35 of the bulb.

When the'component parts of the device are to be united the sleeve 34 is positioned on the reduced portion 33 of the mandrel rod 32. An exhaust tube may then be placed over the sleeve and in the aperture 29 of the support rod 26. Lead wires 27 and 28 which are extensions of the .electrodes supporting refractory element 11 are inserted into pockets in the support rod. The bulb 10 is then disposed over the refractory element with the neck of the bulb surrounding portions of the lead Wire, the bulb being held between jaws 24 and 25. Heating res 3 6 and 37 are then directed to soften the bulb' neck as well as the portion of the exhaust tube within the heat zone and a pair of clamping or press jaws 38 and 39 are operated to compress the plastic glassuniting the several component parts of the device in what is termed the press 16. When the parts have been united the device may be lifted from the support rod 26, the mandrel remaining in place to receive another refractory sleeve.

When the bulb, electrodes, exhaust tube :nd internal sleeve are properly positioned, fires 36 and 37 may be directed against the bulb neck shown in Fig. '5.

While the device is on the exhaust machineV the mercury pool 19 may be introduced into the bulb or the bulb may be inverted to receive the mercury pool before it is inserted into the exhaust machine. As shown in Fig. 5 the quantity of mercury is of such an amount as not to overflow the upper end 42 of the extended portion 22 of the exhaust tube. Thus the device may be evacuated without causing a removal of any of the mercury into the vacuum line.

The present construction provides a device which is of considerable advantage in connection with the manufacture of mercury switches and makes it possible to manufacture the same with a minimum amount of labor and at relatively low cost.

Although a preferred embodiment of the invention is shown and described herein, it is to be understood that modifications may be made therein without departing from the spirit and scope of the invention as set forth in the .ap-f pended claims.

What is claimed is:

1. A mercury switch device comprising an envelope, a press at one end of said envelope, a body of mercury in said envelope and an exhaust tube extending from said press intosaid envelope and above the level of the mercury when the switch is positioned with the extended portion of said tube immersed in said mercury.

2. A mercury switch device comprising an envelope, a quantity of mercury in said envelope, a press at one end of said envelope and an exhaust tube integral with said press and having one end extending' outwardly from said press and the other end extending into said envelope, said last mentioned end being of a length sufiicient to extend above the level of said mercury when the said outwardly extending end is immersed in said mercury.

3. A mercury switch comprising a glass bulb, a body of mercury in said bulb, a glass mass closing one end of said bulb, a. communicating passage through said mass, a tubular member constituting a continuation of said passage and extending a given distance from said mass into said bulb, the free end of said `extending portion being above the level of the mercury body when said body is resting on the glass mass at the foot of said member.

JAMES M. PAGAN. 

